On 7/7/2021 11:48 AM, Anatoly Burakov wrote:
Use RTM and WAITPKG instructions to perform a wait-for-writes similar to what UMWAIT does, but without the limitation of having to listen for just one event. This works because the optimized power state used by the TPAUSE instruction will cause a wake up on RTM transaction abort, so if we add the addresses we're interested in to the read-set, any write to those addresses will wake us up. Signed-off-by: Konstantin Ananyev <konstantin.anan...@intel.com> Signed-off-by: Anatoly Burakov <anatoly.bura...@intel.com> --- Notes: v4: - Fixed bugs in accessing the monitor condition - Abort on any monitor condition not having a defined callbackv2:- Adapt to callback mechanism
Initially I had issues running this as I couldn't see the "rtm" flag in /proc/cpuinfo, but adding "tsx=on" to the kernel parameters resolved this, and rtm was then available to use. Once this was done, I was then able to successfully see power saving when a core was configuired with multiple queues.
Tested-by: David Hunt <david.h...@intel.com>
